Well perforator with positioning tool

ABSTRACT

A tool string of the &#39;&#39;&#39;&#39;pump-down&#39;&#39;&#39;&#39; type including a well perforator in combination with locator and orienting devices for assuring aiming of the perforating charges in a predetermined direction and actuation of the firing mechanism only when the perforator has attained the predetermined aiming direction.

United States Patent Baugh Apr. 18, 1972 54 PE FORATOR WITH 2,785,754 3/ 1957 True ..l75/4.51 1 3,530,948 9/1970 Garrett ..l75/4.5l 3,012,608 12/1961 McLaren ..l75/4.5l [72] Inventor: Hollis A. Baugh, Houston, Tex. 3,040,808 6/1962 Schramm et al. ..175/4.51 X 3,168,141 2/1965 Lebourg ..175/4.51 [73] Assignee: Brown Oil Tools, Inc., Houston, Tex.

- Primary Examiner-David H. Brown [22] Filed. July 13, 1970 Alt0mey R. werlin [21] App1.No.: 54,164

[57] ABSTRACT [52] U.S. Cl ..175/4.5l, 175/452, 166/55.1 A tool string of the "pump-down" type including a well per- [51] Int. Cl ..E21b 43/119 rmer in om inati n with lower and orienting devices for [58] Field of Search 175/451, 4.52; 166/55, 55.1, as ng aiming 0f the perforating charges in a predetermined 166/297 direction and actuation of the firing mechanism only when the perforator has attained the predetermined aiming direction. [56] References Cited 4 Claims, 10 Drawing Figures UNITED STATES PATENTS 3,465,836 9/1969 Fields ..175/4.51

v 62* 7o- A 55 54.4 /5

53-] 54.3 h F j 6 20 5/ Q E-23 5 2/ s \4/ PATENTEDAPR 18 I972 3. 656, 562

- SHEET3UF 4' A TTORNEY PATENTEDAPR 1 8 1912 SHEET H11 '4 Among the relatively recent developments in the equipping of oil wells for production is the use of strings of tools which are pumped through the tubing strings to position various production tools therein and to later remove them if required- The tools which may include gas lift valves, for example, are mounted in a train attached to a so-called motor by means of which the string of tools is pumped up or down the pipe string. The motor is ordinarily a tubular body carrying groups of cup-shaped seal elements sealingly engaging the pipe wall and facing in opposite directions. Thus fluid pressure applied in one direction will drive the train downwardly in the pipe and applied in the opposite direction will drive the train upwardly in the pipe.

Tool strings, as described, are variously known in the industry as Piggy-Back; Through Flow Line (TFL); and Tubing Pump Down (TPD) strings, and ordinarily require the use of dual parallel strings of pipe to accomplish their movement to and from the production pipe string. The second pipe string is employed to deliver pressure fluid into the production pipe string at a point below the tool string when necessary to pump the latter up out of the production string.

In completing wells employing tool strings such as those described, perforators may be run on the tool string to an appropriate location to perforate the tubing and the surrounding earth formations to provide fluid communication between the earth formations and the tubing. However, it is essential that the perforator be angularly oriented so that the jets or bullets discharged therefrom will not strike the companion pipe string or any other production string which may be present in the well bore.

THIS INVENTION In accordance with the present invention, the tool string carrying the perforator also includes a locator unit and an orienting unit which cooperate to rotate the perforator to the desired angular position when the tool string has attained a predeterminedelevation in the pipe string, the attainment of the desired angular position of the perforator being operative to permit actuation of the mechanism for firing the perforator.

The locator unit comprises locator key elements mounted in i the tool string and having particular configurations selectively receivable in landing recesses in the pipe string having matching configurations.

The orienting unit comprises an orienting cam element mounted on the tool string below the related locator key element and an orienting nipple mounted in the pipe string and provided with a spiral cam slot adapted to receive the cam element and to cooperate therewith to rotate the tool string and the perforator carried thereby to the desired angular position when the related locator key element is seated in the corresponding recess.

The locator key and orienting cam elements have coaxial bores to accommodate the firing train which comprises a tubular firing mandrel extending slidably through the several bores to the vicinity of the perforating unit and fitted at its upper end with a piston which is initially secured to the tool string and releasable therefrom by fluid pressure applied through the tool string. An electrical conductor passes through the piston and the bore of the mandrel and is connected to the perforator. The upper end of the conductor is connected to a source of current and a trigger mechanism. The latter is so arranged that it cannot be actuated until the firing mandrel has moved downwardly from its initial position, and such downward movement cannot occur until the locator and orienting elements have attained their predetermined positions.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiment in accordance with this invention.

shown in their running-in or non-actuated positions;

FIG. 2 is a view similar to FIGS. 1B and 1C showing the tool string landed and the firing mechanism in firing position;

FIG. 3 is an elevational view of the orienting nipple;

FIG. 4 is en elevational view of the orienting cam element;

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 4;

FIGS. 6 and 7 are cross-sectional views taken respectively on lines 6-6 and 77 of FIG. 2; and

FIG. 8 is a diagrammatic view of a well extending through a plurality of spaced apart, producing earth formations and equipped with dual pipe strings arranged for use with the present invention.

Referring initially to FIG. 8 of the drawing, there is shown a well bore W intersecting a plurality of spaced apart earth formations R and lined with casing K. A pair of tubing strings T and T extend through the well bore from the surface and are connected together at their lower ends to permit fluid flow from one to the other. Packers P are disposed between the pipe strings and the wall of the well bore to seal off the latter between the several earth formations to define producing zones Z for the severalearth formations. Tubing T,, which will be termed herein the production pipe string, is shown fitted at points intermediate each pair of packers with a section, termed herein the landing section and designated generally by the letter L, adapted to receive and land the tool string for perforating the pipe string in order to provide fluid communication with the related producing zone Z.

Referring now to FIGS. 1A to IC, inclusive, the tool string comprises a plurality of sequentially connected tubular elements including a motor unit, designated generally by the letter A; a firing head, designated generally by the letter B; a locator unit, designated generally by the letter C; a spacer unit D; an orienting unit, designated generally by the letter E; and a perforator F. A firing mandrel, designated generally by the letter G, extends through the bores of the locator and orienting units and provides the operative connection between the firing head and the perforator.

Locator section L is made up of a locator nipple N and a sub-adjacent orienting nipple M which are adapted to cooperate respectively with locator unit C and orienting unit E for landing the tool string and actuating the firing mechanism, as will appear subsequently. Locator nipple N has a locator recess 40 of a predetermined profile configuration including an annular projection 41 intermediate the ends of the recess and having a lower end wall normal to the axis of the nipple to thereby provide a stop shoulder 42 for purposes to be described hereinafter. A liner sleeve 43 is mounted in the bore of orienting nipple M and is provided in the wall thereof with a longitudinally extending spiral cam slot 44 extending over an angular distance somewhat greater than the purpose of which will be more fully described hereinafter.

Motor unit A is of a generally conventional construction comprising a series of tubular motor bodies 10, connected one to another by knuckle or ball-joints 11 to provide the necessary articulation to pemiit passage around wide-radius bends S commonly provided at the upper ends of the pipe strings (FIG. 8) when entering and leaving the latter. The ball-shaped knuckle joints are also designed to permit relative rotation between the several sections of the tool string. Each of the bodies 10 carries a plurality of flexible cup-shaped seal elements 12 which make slidable sealing contact with the bore wall of tubing string T,. Some of the cups face upwardly and some face downwardly to enable movement of the tool string upwardly or downwardly depending upon the direction of flow of pressure fluid supplied through the tubing string. Uppermost body 10 carries a fishing neck 13 by which the tool string may be pulled out of the tubing string by means of wire line tools, if that should prove necessary or expedient.

Firing head B includes a tubular sleeve 14 connected at its upper end by a knuckle joint 11 to the lowermost one of the motor bodies 10. The lower end of sleeve 14 is inserted into the upper end of a firing cylinder 15 and is secured thereto by means of screws 16. A power-pack, designated generally by the letter H, is mounted in the bore of sleeve 14 and closes off the latter. Channels 17 are, therefore, provided to extend through the wall of sleeve 14 to by-pass the power pack and provide fluid communication between the bore of sleeve 14 and the interior of cylinder 15. The lower end of cylinder 15 is connected by means of a knuckle joint 1 1 to the upper end of locator unit C. The exterior of cylinder 15 carries annular seals 18 having slidable sealing engagement with the inner wall of tubing T Locator unit C comprises a tubular body 20 having an axial bore 21 and provided with a plurality of angularly spaced elongate windows 22 in each of which a locator key 23 is mounted for radial movement into and out of locator recess 40. Each of the locator keys has a configuration in longitudinal profile matching that of a particular recess 40. It will be understood that each landing section L will include a locator recess having a different profile than that in each of the other landing sections so that a locator key of a particular profile will be receivable only in a matching recess.

Thus in the drawing which illustrates only one locator recess and one orienting nipple, the profile of locator key 23 will include a recess 24 matching the shape of annular projection 41 and upper and lower edge portions 25 and 26, respectively, which match the corresponding portions of locator recess 40 above and below projection 41. The inner walls of keys 23 are provided with notches 27 defining upwardly facing stop shoulders 28 for purposes to be described more fully hereinafter.

Spacer unit D comprises a tubular body 29 having an axial bore 30 and connected at its upper end by a knuckle joint 11 to the lower end of locator body 20 and at its lower end by a knuckle joint 11 to the upper end of orienting unit E.

Orienting unit E includes a tubular body 31 having an axial bore 32 matching bores 21 and 30 of bodies 20 and 29, respectively, the upper end of body 31 forming part of the knuckle joint connecting the orienting unit to the spacer unit. The lower end of body 31 carries an internally threaded collar 33 for connecting the orienting body to a threaded pin 34 mounted on the upper end of perforator F. As best seen in FIGS. 4 and 5, body 31 is provided with a pair of elongate radial openings 35 in which are mounted a pair of guide vanes 36, 37 arcuate in cross-section, which are hingedly mounted on vertically disposed hinge pins 38 and biased by means of coil springs 39 to swing outwardly into brushing engagement with the wall of tubing T as well as of the inner wall of landing section L. Vane 37 is provided in its outer convex side, near its upper end with an outwardly projecting, cam shaped to be received in close-sliding engagement in cam slot 44 and when so received, to effect rotation of the tool string in response to downward movement of the latter through the landing section, as will be described more fully hereinafter.

Firing mandrel G comprises a generally tubular body 51 adapted to extend from cylinder 15 through the several bores 21, 30 and 32 and terminating at its lower end in a reduced diameter tip 52. Mandrel body 51 is also of articulated construction, being made up of a plurality of sections connected by small knuckle joints 53 to enable the mandrel to bend in correspondence with the bending of the tool string. A piston 54 is mounted on the upper end of mandrel body 51 in slidable sealing relation to the wall of cylinder 15 and is initially secured to the latter by means of one or more shear pins 55 at an upper inactive position. Mandrel body 51 has an axial bore 56 extending from a point below piston 54 through tip 52.

The exterior of mandrel body 51 carries a first set of springpressed pawls 57 which initially engage shoulders 28 in the locator keys and bias the latter outwardly. A second similar pawl 58 is carried by mandrel body 51 and extends into a notch 59 formed in the inner edge of vane 37 and terminating at its lower end in an upwardly facing stop-shoulder 60 which,

by engagement of pawl 58, initially limits downward movement of the firing mandrel relative to the orienting vanes.

Pawls 57 are arranged to have only limited outward movement such that when keys 23 are seated in locator recesses 40, the ends of the pawls will be clear of shoulders 28 (FIG. 2). Pawl 58 similarly has limited outward movement so as to clear shoulder 60 when vane 37 has swung to its outermost position (FIG. 2).

Power pack H includes a tubular shell 61 secured to sleeve 14 by extension of screws 16. A plunger or trigger 62 having an enlarged head 63 on its upper end is slidably mounted in shell 61. The opposite end of trigger 62 projects through an opening 64 in the lower end wall of shell 61 and bears against the upper end of piston 54 being continuously urged thereagainst by a coil spring 65 mounted in compression between trigger head 63 and the upper end wall of shell 61.

Shell 61 contains an electric battery 66 having one lead 67 connected to ground and the second lead 68 to one pole of a normally open switch 69. A firing conductor 70 leads from the other pole of switch 69 through piston 54 and thence through bore 56 of the firing mandrel to a suitable firing initiator (not shown) in perforator F. The arrangement of the firing head is such that when piston 54 and firing mandrel G are moved downwardly, as will be described hereafter, trigger 62 will be freed to move downwardly under the bias of spring 65 sufficiently to close switch 69 and thereby permit firing current to be transmitted from battery 66 to perforator F for firing the latter.

OPERATION In operation the entire string of tools will be inserted into the upper end of tubing string T and by pumping hydraulic fluid into the tubing string behind the tool string, the latter will be forced down the tubing until locator unit C attains a point opposite that landing section L in which the shape of locator recess 40 is matched by the configuration of locator keys 23. At that position the biasing force exerted against pawls 57 will thrust the locator keys into the matching recess with the result that the lower end portions of the keys will engage stop shoulder 42 in the locator recess stopping downward movement of the tool string. Orienting unit E will have been previously spaced from locator unit C by a spacer unit D of appropriate length such that when the locator unit has landed, orienting cam 50 will have entered cam slot 44 under the pressure exerted by coil spring 39 on vane 37 and will have traveled along the cam slot a predetennined distance and in cooperation with the cam slot will cause rotation of the string of tools and the attached perforator F through the requisite angle previously selected to assure directing the perforating charges away from tubing string T When the tool string has thus landed and the perforator is oriented at the proper angle, the continued application of fluid pressure will be transmitted through channels 17 in the firing head against the top of piston 54 until the pressure build-up exceeds the breaking strength of shear pins 55. The latter will then release piston 54 and the firing mandrel will be forced downwardly relative to the anchored tool string a distance such that tip 52 of the firing mandrel will enter a correspondingly shaped recess 70 in the top of the perforator and trigger 62 will be freed to move downwardly so as to close switch 69 and fire the perforator.

It will be seen that the release of the trigger and the firing of the perforator cannot occur until the particular locator unit C and its related orienting unit E have attained their respective landed positions in the landing section. Until keys 23 have moved outwardly into the proper locator recess, pawls 57 will prevent relative longitudinal movement between the firing mandrel and the locator unit, and this will also be true of the engagement of pawl 58 with the orienting unit. Once, however, the locator keys have moved outwardly into the accepting recess and the consequent attainment by the orienting unit of the proper firing position, firing mandrel G can move downwardly so as to release trigger 62. Thus the danger of premature firing of the perforator is eliminated.

When the perforator has been actuated to perforate, for example, the lowermost one of zones Z, the tool string will be either pulled back up tubing string T or pumped back by directing fluid pressure through tubing string T and a new locator unit matching the locator recess in the next higher landing section can be installed in the train. The tool string may then be pumped back down tubing string T to the next higher landing section and the described operations repeated to accomplish perforating of the next higher zone. This operation can be repeated for each of the several zones until all or as many as desired are perforated.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patent is:

l. A well tool string of the pump-down type comprising in combination with means for moving the string through the bore of a well pipe:

a. a perforator carried by the string;

b. selective locator means mounted in the string and in the well pipe cooperable to anchor the string at a selected location in the well pipe;

c. orienting means mounted in the string and well pipe below the locator means cooperable to rotate the tool string and said perforator to a predetermined angular position determined by the longitudinal spacing between the locator means and said orienting means; and

d. firing means mounted in the string actuatable only upon attainment of said angular position by the perforator to fire said perforator; said firing means comprising:

i. a normally open switch;

ii. a current source connected to said switch;

iii. a conductor leading from said switch to said perforator; and

iv. an initially retracted trigger member movable to a switch-closing position by means responsive to said attainment of said angular position of said perforator; said last-mentioned means comprising;

x. a tubular mandrel mounted for movement relative to said locator and orienting means between an upper trigger-retracting position and a lower trigger-releasing position; and

y. means initially securing said mandrel to said string in said upper position and releasable for movement to said lower trigger-releasing position upon attainment by said perforator of said angular position.

2. A tool string according to claim 1 wherein said initially securing means is releasable by fluid pressure transmitted through the tool string.

3. In a tool string according to claim 1, said orienting means comprising:

a. a tubular body mounted in the tool string;

b. a cam element hingedly supported in the body for radial movement toward and away from the wall of said pipe;

c. a spiral cam slot in the wall of said pipe shaped to be engaged by said cam element to force rotation of said tool string in-response to relative longitudinal movement of said tool string; and

d. resilient means biasing said cam element toward the wall of said pipe.

4. A tool string according to claim 3 wherein said cam slot has an angular length greater than 

1. A well tool string of the pump-down type comprising in combination with means for moving the string through the bore of a well pipe: a. a perforator carried by the string; b. selective locator means mounted in the string and in the well pipe cooperable to anchor the string at a selected location in the well pipe; c. orienting means mounted in the string and well pipe below the locator means cooperable to rotate the tool string and said perforator to a predetermined angular position determined by the longitudinal spacing between the locator means and said orienting means; and d. firing means mounted in the string actuatable only upon attainment of said angular position by the perforator to fire said perforator; said firing means comprising: i. a normally open switch; ii. a current source connected to said switch; iii. a conductor leading from said switch to said perforator; and iv. an initially retracted trigger member movable to a switchclosing position by means responsive to said attAinment of said angular position of said perforator; said last-mentioned means comprising; x. a tubular mandrel mounted for movement relative to said locator and orienting means between an upper triggerretracting position and a lower trigger-releasing position; and y. means initially securing said mandrel to said string in said upper position and releasable for movement to said lower trigger-releasing position upon attainment by said perforator of said angular position.
 2. A tool string according to claim 1 wherein said initially securing means is releasable by fluid pressure transmitted through the tool string.
 3. In a tool string according to claim 1, said orienting means comprising: a. a tubular body mounted in the tool string; b. a cam element hingedly supported in the body for radial movement toward and away from the wall of said pipe; c. a spiral cam slot in the wall of said pipe shaped to be engaged by said cam element to force rotation of said tool string in response to relative longitudinal movement of said tool string; and d. resilient means biasing said cam element toward the wall of said pipe.
 4. A tool string according to claim 3 wherein said cam slot has an angular length greater than 180*. 